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High school students' understanding of resistance in simple series electriccircuitsLaurent Ligeois; Etienne Mullet

To cite this Article Ligeois, Laurent and Mullet, Etienne'High school students' understanding of resistance in simpleseries electric circuits', International Journal of Science Education, 24: 6, 551 564To link to this Article: DOI: 10.1080/09500690110066520URL: http://dx.doi.org/10.1080/09500690110066520

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High school students understanding of resistance insimple series electric circuits

Laurent Liegeois, Universite Paul-Valery, Montpellier and Etienne Mullet,Ecole Pratique des Hautes Etudes, France

In view of the lack of work on the understanding of resistance concept, we studied the understandingthat high school students (from the eighth to the twelfth grades) were able to develop with regard to theinterrelationships between this concept, and the potential difference and current concepts (Ohms law).In addition, we explored the immediate effects of exposure to electricity courses on the intuitive masteryof these relationships. The participants were presented with information on potential difference andintensity of current and asked to predict the corresponding resistance values. In this current-potentialdifference context, the resistance concept was difficult to understand. For the majority of participants,resistance was a direct function of both current and potential difference, which is more reminiscent ofthe concept of power than of the concept of resistance. The systematic teaching of electricity conceptsand Ohms law had only limited, positive as well as negative, effects on the understanding of theserelationships. The implications for education are discussed.

Introduction

The understanding of electricity concepts by young pupils (Fleer 1994), highschool students, and college and university students (Borges and Gilbert 1999,Shepardson and Moje 1999) has been the focus of many studies in psychologyand education. The concepts investigated include electric circuits (Andre and Ding1991), electric diagrams (Johsua and Dupin 1985), current (Rozencwajg 1992), andpotential difference at battery terminals (Millar and Beh 1993, Millar and King1993). However, to our knowledge, the concepts of resistance and the concept ofpower have not been extensively investigated (see, Psillos and Koumaras 1993).

It has been repeatedly shown that pupils, students, and even their teachers(Webb 1992, Wiles and Wright 1997), as well as practitioners (Borges and Gilbert1999), share a number of misconceptions about these notions (see, Chan et al.1998, for a review). These misconceptions were observed in various countrieseach having distinct educational systems (Shipstone et al. 1988).

Misconceptions among young children and young adolescents

In young children, electrical current is frequently considered as being transferredfrom batteries to light bulbs in a similar way to how orange juice is transferredfrom a bottle to the mouth using a straw (the sink model, Fredette and Lochhead1980). Hence, the possible reason why the popular term juice is used by some todesignate electrical current. In young adolescents, the light in a bulb is frequently

International Journal of Science Education ISSN 09500693 print/ISSN 14645289 online# 2002 Taylor & Francis Ltdhttp://www.tandf.co.uk/journals

DOI: 10.1080/09500690110066520

INT. J. SCI. EDUC., 2002, VOL. 24, NO. 6, 551564

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considered as the result of the clashing between the positive current coming fromthe positive side of the battery, and the negative current coming from the negativeside (Osborne 1983).

For young adolescents and even for some college students, an electric circuitdoes not need to be closed to be operative. In addition, evident short-circuits in anelectrical circuit are not easily detected (Johsua 1984).

Misconceptions among students: the localist approach

Previous research has shown that when reasoning about an electrical circuit, manystudents are unwilling to consider it as a whole where elements are totally inter-dependent. Students usually approach electrical circuits in a localist way and in asequentialist way (Cohen et al. 1983, Closset 1984). The localist approach is char-acterized by the fact that each part of the circuit tends to be treated separately. Inthe circuit given in figure 1, the battery, the left segment with its ammeter, theresistance and its associated voltmeter, are considered as separate elements. Thesequentialist approach is characterized by the fact that some parts of the circuittend to be considered before other parts. In the circuit given in figure 1, the leftsegment with its ammeter portion of the circuit will be considered before (or after)the resistance and its associated voltmeter portion, and the resistance and its as-sociated voltmeter portion will, in turn, be considered before (or after) the rightsegment. As a result, a phenomenon affecting one part of the circuit will bereflected in the subsequent portions of the circuit without affecting the precedingportions.

Misconceptions among students: confusing potential difference andcurrent

Previous research has also shown that the concept of potential difference is adifficult one for pupils and students to master. The main reason for this difficultyis that everyday experience with regards to potential difference is probably lacking

552 L. LIEGEOIS AND E. MULLET

Figure 1. Example of material presented to the participants.

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for most people (with the exception perhaps of those who travel frequently fromEurope to America and vice versa, and who are therefore familiar with voltageadaptors).

From the physicists point of view (Psillos and Koumaras 1993), potentialdifference refers to the inequality of charge between the battery terminals. Thisinequality of charge results from chemical reactions inside the battery (the separa-tion of positive and negative charges, and their accumulation on opposite sides).Potential difference is at the origin of the electric current, that is, at the origin ofthe motion of the free electrons in the conductor in order to replace the missingelectrons in the positive battery terminal. Potential difference resulting from elec-trochemical reactions inside the battery has a constant value. Students, as well asmost non-professionals in the field, tend to share the reverse point of view, that is,to view electrical current as the origin of potential difference and potential differ-ence as a mere measure of electric flow, more or less synonymous with intensity ofcurrent. In addition, electrical current is usually viewed as dissipating through thediverse elements of the circuit, especially bulbs (resistors).

Finally, previous research has shown that the concept of current is easier tomaster than the concept of potential difference (Psillos et al. 1988). From thephysicists point of view (Psillos and Koumaras 1993), electrical current refersto the motion of the free electrons of the conductor in order to replace the missingelectrons in the positive battery terminal: current is a measure of that flow. Themore electrons passing through some portion of the conductor per unit of time, thegreater the current. The students and the non-professionals conceptions of cur-rent are not very far from the scientific point of view.

The present study

There has been much less research on the understanding of resistance conceptsthan on the understanding of current and potential difference (Psillos andKoumaras 1993). From the physicists point of view, resistance is due to thefriction of the moving electrons with the conductor/resistor ions (Psillos andKoumaras 1993). As a result, the greater the friction, the less the electrons flow(less current), and the greater the potential difference (inequality of charges) at theterminals of the resistor. Resistance is a constant property of the resistor at a giventemperature.

Students, and most non-professionals in the field, tend to view resistors essen-tially as sources of heat (or light), that is to say as the locus of the dissipation ofcurrent (Cohen et al. 1983). This is due to the fact that everyday experience withresistors is through the use of light bulbs or radiators. Other domestic appliancesare not viewed as resistors.

In view of the lack of work on the understanding of the resistance concept, wedecided to study the understanding that high school students (from the eighth tothe twelfth grades) were able to develop with regard to the interrelationshipsbetween this concept, and the potential difference and current concepts. In addi-tion, we also wanted to explore the immediate effects of exposure to electricitycourses on the intuitive mastery of these relationships.

The problem was approached in what Millar and Beh (1993: 152) termed aninstrumentalist way, and what Millar and King (1993: 348) refer to as an obliqueapproach. We wanted to study what participants do concretely with current and

UNDERSTANDING OF RESISTANCE IN ELECTRIC CIRCUITS 553

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potential difference information when inferring resistance. What information dothe participants take into account? And in what way? How do they combine infor-mation?

As stated by Millar and Beh, the ability to predict voltmeter readings insimple series circuits is one part of what we might mean by an understandingof voltage (p. 348). This statement by Millar and Beh could easily be extended toresistance by saying that the ability to predict resistance values is one part of whatwe might mean by an understanding of resistance.

Understanding resistance

According to Ohms law: ResistancePotential difference / Current. The under-standing of this equation, that is, according to Millar and Beh, the ability to use itto predict resistance values, presupposes: (a) the recognition of a relationshipbetween potential difference and resistance; (b) the recognition of a relationshipbetween current and resistance; (c) the recognition of the direct relationshipbetween potential difference and resistance; (d) the recognition of an inverse rela-tionship between current and resistance; (e) the recognition of the fact that theserelations are the only relevant ones; and (f) the recognition of the fact that adivision operation needs to be applied.

The correct pattern of results corresponding to this equation is shown in figure2. On the horizontal axis are three current levels. On the vertical axis are computedresistance values. The three curves in each panel correspond to three possiblepotential difference values. The two panels correspond to two possible positionsof the ammeter (before and after the resistor). In each panel, both curves were


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On the horizontal axis are shown three intensity of current levels. On the vertical axis are computedresistance values. The three curves in each panel correspond to three possible potential differencevalues. The two panels correspond to two possible positions of the ammeter (before and after theresistor).

Figure 2. Theoretical pattern of results.

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descending: the higher the intensity of the current, the lower the resistance. Ineach panel, curves were clearly separated: the higher the potential difference, thehigher the resistance. In each panel, both curves were at the same level on thevertical axis; the position of the ammeter had no effect on the value of resistance.In each panel, the curves form a linear fan opened to the left with the highpotential difference curve on the top of the low potential difference curve; thecombination of potential difference and current obeyed a division rule.

The understanding of the concept of resistance may be defective for a numberof independent or associated reasons. We can consider a case in which a student ispresented with the electrical circuit shown in figure 1. This student has (pictorial)information on potential difference (low or high) and current (low or high) and isasked to infer the resistance of the resistor. The student may in fact only take thecurrent information into account (if current is high, that means that current flowseasily through the resistor and that resistance is low, irrespective of the potentialdifference level). In contrast, the student may only take potential difference intoaccount (resistance and potential difference can be seen as referring to the sameobject, the resistor).

The student may take the current information into account without realizingthat the relationship is negative (the greater the current, the greater the resistance).As shown by numerous authors, most students and most non-professionals in thefield insufficiently discriminate between current and potential difference. Potentialdifference and current are viewed as basically the same phenomenon (a meremeasure of electric current) or at least as very similar phenomena. As a conse-quence, the direction of the relationship between potential difference and resist-ance, and the relationship between current and resistance, can not be easilyconceived as having opposite signs: a direct relationship in the case of potentialdifference, and an inverse relationship in the case of current.

Finally, the student may intuitively combine the two pieces of information butin a sub-optimal way, for example subtractively, and/or inference may be con-taminated by irrelevant information (position A or A of the ammeter in the cir-cuit).

Functional theory of cognition

The methodological framework for this study was the Functional Theory ofCognition (Anderson 1996). This theory provides a description of the algebraicstructure of the cognitive processes underlying the integration of multiple pieces ofinformation (potential difference and current, for example) into a single judgement(resistance, for example). Functional measurement methodology has been appliedsuccessfully in a variety of related fields: intuitive geometry (Mullet and Miroux1996, Rulence-Paques and Mullet 1998), intuitive number sense (Cuneo 1982,Munoz Sastre and Mullet 1998), and intuitive physics (Mullet and Gervais1990, Anderson and Wilkening 1991).

The major advantages of this method are that, (a) it yields true linear responsescales; and (b) it can successfully account for integration processes in algebraicterms. Both advantages are of vital importance in intuitive physics studies. Theyallow for considering and interpreting not only main effects (effect of potentialdifference on resistance, for example) but also interactions. In the study of theconcept of resistance, the potential difference X current interaction plays a major


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role. Functional measurement methodology has been chosen over otherapproaches because it allows for easily assessing and testing this interaction.

Hypotheses

It can be hypothesized, based on the work by Stavy and Tirosh (1996) and byAndersson (1986), that when asked to infer resistance from potential differenceand current information, pupils from eighth and ninth grades would take intoaccount: (a) potential difference information in a direct way (the greater the poten-tial difference, the greater the resistance); as well as (b) current information in adirect way (the greater the current, the greater the resistance). According to Stavyand Tirosh (1996) students commonly use a kind of More of AMore of B rulewhen confronted with comparison tasks or inference tasks in various physical ormathematical settings (see also, Tirosh and Stavy 1999). According to Andersson(1986), this could be due to the kind of experiential gestalt of causation pupils havederived from everyday life (the greater the effort he makes, the bigger the effect onthe object, Andersson 1986: 157). It can also be hypothesized that, due to theirlocalist-sequentialist approach, pupils from eighth and ninth grades would alsoconsider that the resistance value is dependent on the position of the ammeter inthe circuit (before or after the resistor).

It can be hypothesized that tenth, eleventh and twelfth graders, who have beenexposed to many electricity lessons, including Ohms law, and who have conductedmany electricity experiments in class, would (a) take into account potential differ-ence information in a direct way and current information in an inverse way, butapply a less than normative combination (subtractive), and (b) be less sensitive toirrelevant information. Finally, it can be hypothesized that just after exposure toelectricity lessons all participants would show better performance with regards tothe use of current and potential difference information, and would be better able todisregard irrelevant information than before exposure.

Method

Participants

Participants were 100 students of various ages, and various school levels: 20eighth-graders (12 girls and 8 boys, mean age 13.9), 20 ninth-graders (9 girlsand 11 boys, mean age 15.1), 23 tenth-graders (14 girls and 9 boys, meanage 16.3), 20 eleventh-graders (15 girls and 5 boys, mean age 17.6), and 17twelfth-graders (9 girls and 8 boys). All students resided in Reims, France andvolunteered for participation in the study. The average academic ability of eachgroup was not different from the average academic ability of the students in thearea. In addition, they were all from the same school district, that is they all hadthe same general geographical and socio-economic background.

As basic electricity concepts are taught at each of the mentioned grades,students in the eighth grade had not previously learned about electricity conceptsat the time of the first phase of the experiment; students in the ninth grade hadparticipated in one course about electricity concepts (the year before the study);students in the tenth grade had participated in three courses; students in the


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eleventh grade had participated in four courses; and students in the twelfth gradehad participated in a total of five courses.

Material

The material was composed of one series of 18 cards. On each card, an electricalcircuit was printed (see figure 1). Under the circuit was a 16-cm response scalewhere the left anchor was No resistance, and the right anchor was High resist-ance. The series of 18 cards was obtained by an orthogonal crossing of the threefactors describing the circuit: intensity of current (low, medium, high), potentialdifference (low, medium, high), and position of the ammeter (A or A).

Procedure

Participants were tested both before and after exposure to a course on electricitygiven at school. In both cases, the procedure was the same. It consisted of twophases. The first phase familiarized the participants with the material. The 18cards were presented in random order. The participants were asked to examineeach electrical circuit and place a mark on the resistance scale at what she or hebelieved to be the actual resistance value according to the position in the circuit ofthe ammeter, to the value shown by the ammeter, and to the value shown by thevoltmeter. At the end of this phase, the participants were allowed to compare theirresponses and change their ratings until they were satisfied with the entire set ofratings. During this phase, information was provided before and during the test,with regards to the different elements of the circuit: battery, resistors, voltmeter,and ammeter.

The second phase was the test phase proper. It was identical to the first phaseexcept that the participants were no longer allowed to compare their responses,and that the 18 cards were embedded in a larger set of cards. (The responses givento the additional cards will be treated in a separate study). Participants workedindividually at their own pace in a quiet room on the school grounds.

Results

The distance in centimetres between the No Resistance anchor and each parti-cipants marks was measured for phase 2. The participants used the entire range ofthe response scale for their ratings (from 0.1 to 15.90).

Cluster analysis

A cluster analysis (Complete Linkage) was performed on the whole set of data inorder to determine possible different groups of participants. A five-cluster solutionwas chosen because it was the one best showing the diverse rules used. Resultscorresponding to these clusters are presented in figures 3 and 4.

The top panels in figure 3 plot the values observed for Cluster I. On thevertical axis are the estimated resistance values. The curves were ascending: thehigher the current, the higher the judged resistance; and the curves were separated:the higher the potential difference, the higher the resistance. In both panels, thecurves were at the same level on the vertical axis; the position of the ammeter


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information was not taken into account for judging resistance. In each panel, thedata panel formed a set of parallel lines; potential difference and current werecombined following an additive law.

The bottom panels in figure 3 plot the values observed for Cluster II. Thecurves were descending: the higher the current, the lower the judged resistance;and the curves were separated: the higher the potential difference, the lower theresistance. In both panels, the curves were at the same level on the vertical axis; theposition of the ammeter information was not taken into account for judging resist-ance. In each panel, the data pattern was slightly fan shaped and open on the right;potential difference and current were not combined according to a strictly additivelaw.

The top panels in figure 4 plot the values observed for Cluster III. The curveswere flat: the current information was not taken into account for judging resist-ance. The curves were clearly separated: the higher the potential difference, the


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On the horizontal axis are shown three intensity of current levels. On the vertical axis are inferredresistance values. The three curves in each panel correspond to three possible potential differencevalues. The two panels correspond to two possible positions of the ammeter (before and after theresistor).

Figure 3. Observed patterns of results: clusters I and II.

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higher the resistance. In both panels, the curves were at the same level on thevertical axis; the position of the ammeter information was not taken into accountfor judging resistance.

Finally, the bottom panels in figure 4 plot the values observed for Cluster IV.The data pattern was complex. When potential difference was low, current wastaken into account in a direct way for judging resistance. When potential differencewas high, current was taken into account in an inverse way for judging resistance.Finally, when potential difference was medium, current was taken into accountin an inverse way and then in a direct way for judging resistance. When theammeter was on the left, current effects were higher than when the ammeterwas on the right.


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Cluster IV

On the horizontal axis are shown three intensity of current levels. On the vertical axis are inferredresistance values. The three curves in each panel correspond to three possible potential differencevalues. The two panels correspond to two possible positions of the ammeter (before and after theresistor).

Figure 4. Observed patterns of results: clusters III and IV.

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The values for Cluster V are not shown. Participants in Cluster V only usedthe current information. Curves were ascending and merged.

Effect of exposure to electricity courses

Table 1 presents the results relative to the effect of exposure to electricity courseson the resistance judgements. Before exposure, a majority of participants45 23 68 took into account the potential difference information for judgingresistance in a direct and correct way. After exposure, the global picture evolvedslightly. The number of participants who took into account the potential differenceinformation in a direct way was 74 61 13. Before exposure, the potential dif-ference information was taken into account in an inverse way for judging resistanceonly by a minority (13). After exposure, the global picture evolved slightly. Thenumber of participants who took into account the potential difference informationin an inverse way dropped to 5.

Before exposure, a minority of participants (13) took into account the currentinformation for judging resistance in an inverse and correct way. After exposure,the global picture deteriorated. The number of participants who took into accountthe current information, in an inverse way, was 5. Before exposure, many partici-pants (45) took into account, in a direct, incorrect way, the current information forjudging resistance. After exposure, the global picture was clearly poorer. Thenumber of participants who took into account the current information in a directway was 61.

Discussion

It was hypothesized that when asked to infer resistance from potential differenceand intensity of current information, eighth and ninth graders would take into


Table 1. Composition of the clusters (before and after exposure to elec-tricity courses).

Clusters Clusters (After Exposure) Grade Levels(BeforeExposure) I II III IV V 8th 9th 10th 11th 12th Total

I 37 1 2 0 5 11 15 5 12 2 45II 7 2 0 1 3 3 4 2 2 2 13III 9 1 8 2 3 3 1 7 3 9 23IV 5 1 3 1 3 2 0 7 2 2 13V 3 0 0 0 3 1 0 2 1 2 6

Grade Levels I II III IV V Total

8th 10 2 0 0 8 209th 16 2 1 0 1 2010th 16 1 4 1 1 2311th 16 0 1 1 2 2012th 3 0 7 2 5 17

Total 61 5 13 4 17 20 20 23 20 17 100

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account: (a) potential, difference information in a direct way; as well as (b) currentinformation in a direct way. This is what was observed. More than half of theyounger high school students used both pieces of information in a direct way.

It was hypothesized that, due to their localist-sequentialist approach, pupilsfrom eighth and ninth grades would also consider that the resistance value isdependent on the position of the ammeter in the circuit (before or after the resis-tor). This was not observed.

It was hypothesized that at least some tenth, eleventh and twelfth gradestudents would take into account potential difference information in a directway and current information in an inverse way but, apply a less than normativecombination (subtractive). This hypothesis was not supported. Older high schoolstudents used potential difference and current information in a way very similar tothat which the younger high school students did. Very few used current informa-tion in an inverse way and, when they did so, they also used potential differenceinformation in an inverse way. Overall, high school students were not able to usepotential difference and current information in a different way. The combinationrule used can be expressed in the following equations:

Resistance Potential difference Current 4 majority ruleResistance Potential difference Current 5 minority rule

It was hypothesized that tenth, eleventh and twelfth graders, would be less sensi-tive to irrelevant information. This was not observed, essentially because youngerstudents were not sensitive to the ammeter position information.

Finally, it was hypothesized that just after exposure to electricity lessons allparticipants would show better performance with regards to the use of current andpotential difference information and would be better able to disregard irrelevantinformation than before exposure. Exposure to an electricity course was mildlysuccessful. After exposure, more high school students took into account, (a) thepotential difference information in a direct, correct way; and (b) the current infor-mation in a direct, incorrect way. The effect of exposure to courses was, thus,shown to be positive as well as negative. This is consistent with previous studies.As already stated by Andersson (1986), scientific concepts only develop to a minorextent as a result of teaching (Andersson 1986: 155).

The resistance concept was thus very difficult to understand in the current-potential difference context chosen in the present study. For a majority of parti-cipants, irrespective of age and training, resistance was a direct function of bothcurrent and potential difference. The current-potential difference confusion,shown by numerous authors, was clearly detrimental because potential differenceand current have to be considered as having completely different effects on resist-ance: direct effect for potential difference, and the inverse for current.

As a result of this confusion, when through some kind of estimation procedureresistance is found to be lower whereas current has, at the same time, decreased,the attention of the average student will not be alerted toward this inconsistentresult, and the estimation procedure will not be revised. Worse, that resistancedecreases at the same time that current decreases could be welcomed by the aver-age student as reassuring (the More of A more of B rule); and that resistancedecreases at the same time that current increases could be considered by theaverage student as indicating that the estimation procedure has to be revised.


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The rule used by most participants to infer resistance: ResistancePotentialdifferenceCurrent is, in fact, much more reminiscent of the equation used forcomputing power than of Ohms law. This rule is exactly what Anderssons experi-ential gestalt of causation predicts. One component of Anderssons model is thegreater the effort, the bigger the effect. This component was applied here by mostparticipants with regards to the bivariate relationship between current and resist-ance, and the bivariate relationship between potential difference and resistance.Another component of this model is several agents have a greater effect than justone (Andersson 1986: 157). This component was applied here by most partici-pants in terms of the mutivariate relationship between current, potential differenceand resistance. For these participants, current and potential difference add theireffects.

One could wonder if the material used in the present study confused partici-pants by being unusual or complex. In practice, no participant expressed anydegree of difficulty with the material. Moreover, the participants were used tothe type of electrical schemas used here, which were less complex than thoseusually found in most textbooks.

One could also wonder if Ohms law was actually an important part in theelectricity programme, and if enough teaching time hours were devoted to it. It issurprising to find out that Ohms law is in fact a major constituent of the electricityprogrammes from the ninth grade to the twelfth grade. Teachers insist that theunderstanding of Ohms law, and the correct use of the corresponding equations isone of the major pedagogical objectives in class.

Implications for education

Our guess is that in order to facilitate an understanding among pupils of therelationships between the components of Ohms law, some kind of functionalteaching has to be used to complement traditional teaching. This type of functionalteaching could be provided with computers (see also, Ronen and Eliahu 2000).

Firstly, pupils could be presented with simplified electrical schemas (see figure1) and asked to infer potential difference from current and resistance (qualitative)information. Responses should be given in a non-numeric format (length of barsfor example), and feedback could be provided online in the same format. Previousstudies using similar techniques have shown that, when both relationships aredirect, learning occurs quickly and efficiently (Doherty and Kurz 1996). It remainsto be shown, however, if this kind of technique can lead pupils to the intuition thatthe relationship is more than additive.

Second, pupils could be presented with similar, simplified electrical schemasand asked to infer current from potential difference and resistance information.Responses should also be given in a non-numeric format, and feedback providedonline in the same way. Two previous experiments (Chasseigne et al. 1997) usingsimilar techniques have shown that, when one relationship is direct and one rela-tionship is inverse, learning occurs but not as quickly or efficiently as when bothrelationships are inverse. It is not known if this kind of technique can lead pupils tothe intuition that the relationship is more than subtractive.

Third, and finally, pupils could be asked to infer resistance of a resistor fromcurrent and potential difference information and be given feedback. In all threecases, feedback could also be given in various formats, including factorial graphs


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likes the ones presented in figure 2. Finally, pupils could be offered the oppor-tunity to visualize their progression in understanding, through visualization oftheir results pattern as it transforms as a result of their functional learning.

Acknowledgement

This work was supported by the Laboratoire Cognition and Decision of the EcolePratique des Hautes Etudes, by the UPRES Vieillissement, Rythmicite etDeveloppement Cognitif, and by the UMR Travail et Cognition. We are gratefulto Sheila Rivie`re Shafighi, Stacey Callahan, and Gerard Chasseigne for theirthoughtful comments on an earlier draft of this article.

References

Anderson, N. H. (1996) A Functional Theory of Cognition (Mahwah, NJ: Erlbaum).Anderson, N. H. andWilkening, F. (1991) Adaptive thinking in intuitive physics. In N. H.

Anderson, Contributions to Information Integration Theory (Hillsdale, NJ: Erlbaum).Andersson, B. (1986) The experiential gestalt of causation: A common core to pupils

preconceptions in science. European Journal of Science Education, 8, 155171.Andre, T. and Ding, P. (1991) Students misconceptions, declarative knowledge, stimulus

conditions, and problem solving in basic electricity. Contemporary EducationalPsychology, 16, 303313.

Borges, A. T. and Gilbert, J. K. (1999) Mental models of electricity. International Journalof Science Education, 21, 95117.

Chang, K.-E., Liu, S. H. and Chen, S. W. (1998) A testing system for diagnosing mis-conceptions in DC electric circuits. Computers and Education, 31, 195210.

Chasseigne, G., Mullet, E. and Stewart, T. (1997) Aging and probability learning: thecase of inverse relationships. Acta Psychologica, 97, 235252.

Closset, J.-L. (1984) Sequential reasoning in electricity. In Research on Physics Education:Proceedings of the First International Workshop (Paris: CNRS), 313319.

Cohen, R., Eylon, B. and Ganiel, U. (1983) Potential difference and current in simpleelectric circuits: a study of students concepts. American Journal of Physics, 51, 407412.

Cuneo, D. (1982) Childrens judgments on numerical quantity: a new view of early quanti-fication. Cognitive Psychology, 14, 1344.

Doherty, M. E. and Kurz, E. (1996) Social judgment theory. Thinking and Reasoning, 2,109140.

Fleer, M. (1994) Determining childrens understanding of electricity. Journal ofEducational Research, 87, 248253.

Fredette, N. and Lochhead, J. (1980) Students conceptions of simple circuits. The PhysicsTeacher, 18 194198.

Johsua, S. (1984) Students interpretation of simple electrical diagrams. European Journal ofScience Education, 6, 271275.

Johsua, S. and Dupin, J. J. (1985) Schematic diagrams, representations and types of reason-ing in basic electricity. In R. Duit, W. Jung, H. Pfund and C. von Rhoneck (eds)Aspects Of Understanding Electricity (Kiel: IPN), 129138.

Millar, R. and Beh, K. L. (1993) Students understanding of voltage in simple parallelcircuits. International Journal of Science Education, 15, 351361.

Millar, R. and King, T. (1993) Students understanding of voltage in simple series electriccircuits. International Journal of Science Education, 15, 339349.

Mullet, E. and Gervais, H. (1990) Distinction between the concepts of weight and mass inhigh school students. International Journal of Science Education, 12, 217226.

Mullet, E. and Miroux, R. (1996) Judgment of rectangular areas in children blind frombirth. Cognitive Development, 11, 123139.


Downlo

aded

By:

[Au

stra

lian

Nat

iona

l Un

iver

sity

Lib

rary

] At

: 07

:35

13 N

ovem

ber

2009

MuNoz Sastre, M. T. and Mullet, E. (1998) Evolution of the intuitive mastery of therelationship between base, exponent, and number magnitude in high school students.Mathematical Cognition, 4, 6777.

Osborne, R. (1983) Toward modifying childrens idea about electric current. Research inScience and Technological Education, 1, 7382.

Psillos, D. and Koumaras, P. (1993) Multiple causal modeling of electrical circuits forenhancing knowledge intelligibility. In M. Caillot, Learning Electricity andElectronics with Advanced Educational Techniques (New York: Springer Verlag), 5775.

Psillos, D., Koumaras, P. and Tiberghien, A. (1988) Voltage presented as a primary con-cept in an introductory teaching sequence on DC circuits. International Journal ofScience Education, 10, 2943.

Ronen, M. and Eliahu, M. (2000) Simulation a bridge between theory and reality: thecase of electric circuits. Journal of Computer Assisted Learning, 16, 1426.

Rozencwajg, P. (1992) Analysis of problem solving strategies on electricity problems in 12to 13 year olds. European Journal of Psychology of Education, 7, 522.

Rulence-PAques, P. and Mullet, E. (1998) Perception of surface and inference of surface:the case of the rectangle. Journal of Experimental Child Psychology, 69, 127.

Shepardson, D. P. and Moje, E. B. (1999) The role of anomalous data in restructuringfourth graders frameworks for understanding electric circuits. International Journalof Science Education, 21, 7794.

Shipstone, D. M., von RhOneck, C., Jung, W., KArrqvist, C., Dupin, J.J., Johsua, S. andLicht, P. (1988) A study of studentsunderstanding of electricity in five Europeancountries. International Journal of Science Education, 10, 303316.

Stavy, R. and Tirosh, D. (1996) Intuitive rule in mathematics and science: the case of Themore of Athe more of B. International Journal of Science Education, 18, 653667.

Tirosh, D. and Stavy, R. (1999) Intuitive rules: a way to explain and predict studentsreasoning. Educational Studies in Mathematics, 38, 5166.

Webb, P. (1992) Primary science teachers understandings of electric current. InternationalJournal of Science Education, 14, 423429.

Wiles, N. and Wright, D. (1997) A hypermedia system to aid teacher understanding ofpupil preconceptions. Journal of Computer Assisted Learning, 13, 2634.

564 UNDERSTANDING OF RESISTANCE IN ELECTRIC CIRCUITS

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Laurent Liégeois, 2002- listrik dinamis.pdf

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